A crack in a viscoelastic solid exhibits velocity jump, i.e., the propagation changes abruptly narrow range of applied load. However, mechanism had been unsolved until recently. This review introduces past findings on jumps solids, focusing our studies. We have developed an exactly solvable model that jump. From mathematical solution, we elucidated jump is caused by dynamic glass transition vic...

The geometry of postmortem rough fracture surfaces of porous glass ceramics made of sintered glass beads is shown experimentally to be self-affine with an exponent zeta=0.40+/-0.04, remarkably lower than the "universal" value zeta=0.8 frequently measured for many materials. This low value of zeta is similar to that found for sandstone samples of similar microstructure and is also practically in...

The mesoscopic concept is a way to deal with complex materials with an internal structure within continuum mechanics. It consists of extending the domain of the balance equations by mesoscopic variables and of introducing a local distribution function of these variables as a statistical element. In our case microcracks are modelled as penny shaped and completely characterized by their diameter ...

In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage,...

RICE et ml. (1994, J. Mech. Ph_vs. Solids 42, 813-843) analyse the propagation of a planar crack with a nominally straight front in a model elastic solid with a single displacement component. Using the form of their results for a strictly linearized perturbation from a straight crack front which moves at uniform speed, we give the corresponding first-order expression for the deviation of a crac...

Comment on " Crack street: The cycloidal wake of a cylinder tearing through a thin sheet " A new mode of oscillatory fracture in brittle thin films has recently been reported in two independent experiments [1, 2]. When an object is driven through a thin film clamped along its lateral boundaries, the film tears following a striking sawtooth pattern, as the crack tip propagates in an oscillatory ...

Colloidal dispersions are known to display a fascinating network of cracks on drying. We probe the fracture mechanics of free-standing films of aqueous polymer-particle dispersions. Thin films of the dispersion are cast between a pair of plain steel wires and allowed to dry under ambient conditions. The strain induced on the particle network during drying is relieved by cracking. The stress whi...

Nondestructive testing of concrete allows the inspection of larger areas of concrete members at lesser cost than coring and provides more information than visual inspection. This paper addresses a new approach for determining the positions and size of cracks in concrete members by using ultrasonic pulse velocity test. Three plain concrete beams, containing artificial cracks (30 – 60% of the bea...